. Morphology of gymnosperms. Gymnosperms; Plant morphology. CYCADOFILICALES 29 occur structures, of the Calymmaiotheca type. It must be confessed that while the Crossotheca or "epaulet" type of stamen is distinct. 22 -23 Figs. 22, 23.—Crossotheca Honinghausii: fig. 22, diagrammatic longitudinal section of stamen; fig. 23, diagrammatic transverse section of stamen; /, limb; s, spo- rangia; m, rock matrix.—After Kidston (64). enough, the so-called Calymmaiotheca or "cupule" type is in con- fusion, and so far as it represents microsporangiate structures at all, they may be ref
. Morphology of gymnosperms. Gymnosperms; Plant morphology. CYCADOFILICALES 29 occur structures, of the Calymmaiotheca type. It must be confessed that while the Crossotheca or "epaulet" type of stamen is distinct. 22 -23 Figs. 22, 23.—Crossotheca Honinghausii: fig. 22, diagrammatic longitudinal section of stamen; fig. 23, diagrammatic transverse section of stamen; /, limb; s, spo- rangia; m, rock matrix.—After Kidston (64). enough, the so-called Calymmaiotheca or "cupule" type is in con- fusion, and so far as it represents microsporangiate structures at all, they may be referred ultimately to Crossotheca or to ordinary marattiaceous synangia, like those of Kaulfussia. Although actual organic connection of stamens with plants known to be seed-bearing has been discovered as yet in only two or three forms, it is evident that a much wider range of forms is indicated. All structures of the Crossotheca type may fairly be considered probable stamens of Cycadofilicales, and some of the Calymmatotheca structures, so far as they are distinct from large marattiaceous synangia, are doubtless such also. It must be noted, however, that the frond genera and the sporangium genera cross one another's boundaries. For example, Crossotheca occurs on both Sphenopteris and Pecopteris; while Calym^ matotheca (or its equivalents) occurs on Neurop- teris, Sphenopteris, and probably Aneimites. The dimorphic charac- ter of the fronds is quite marked in all these cases, and it sug- gests the question whether other dimorphic fronds, bearing sporangia of a different type, may not belong to Cycadofilicales. Furthermore, the great frond genus Pecopteris, one of whose species, at least, is known to belong to the Cycadofilicales, possesses all the types of spo- FiG. 24.—Codo- notheca; X2.—After Sellaeds (40).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illu
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